Vehicle security systems are widely used to deter vehicle theft, prevent theft of valuables from a vehicle, deter vandalism, and to protect vehicle owners and occupants. A typical automobile security system, for example, includes a central processor or controller connected to a plurality of vehicle sensors. The sensors, for example, may detect opening of the trunk, hood, doors, windows, and also movement of the vehicle or within the vehicle. Ultrasonic and microwave motion detectors, vibration sensors, sound discriminators, differential pressure sensors, and switches may also be used as sensors. In addition, radar sensors may be used to monitor the area proximate the vehicle. The controller also typically operates to give an alarm indication in the event of triggering of a vehicle sensor. The alarm indication may typically be a flashing of the lights and/or the sounding of the vehicle horn or a siren. In addition, the vehicle fuel supply and/or ignition power may be selectively disabled based upon an alarm condition.
A typical security system also includes a receiver associated with the controller that cooperates with one or more remote transmitters typically carried by the user as disclosed, for example, in U.S. Pat. No. 4,383,242 to Sassover et al. The remote transmitter may be used to arm and disarm the controller in the vehicle or provide other remote control features from a predetermined range outside the vehicle.
Many other features may be incorporated into a vehicle security system. For example, as disclosed in U.S. Pat. No. 4,887,064 to Drori et al. The controller may include self-diagnostics. A flashing LED, sound signal, or voice message may be used to give an indication that the alarm has been triggered. The audible alarm signal may be selected by the user. An alarm may also be given when power is restored after having been disconnected, as when a thief disconnects the power to avoid the security system and attempts to then start the vehicle. An LED is mounted on the vehicle instrument panel or dashboard so that the controller may visually communicate with the user. A keypad may also be mounted within the vehicle to permit the user to program certain features of the security system. Control functions may also be implemented by the security system including: accessory, pulsed alarm, hood release, ignition cutoff, door lock and unlock.
A vehicle security system may also include a passive arming feature wherein the status of all trigger inputs is monitored in several protection zones. These zones may include the passenger compartment, the engine compartment, the trunk, and additional sensor zones such as for motion, impact, and or glass breakage. When the ignition key is turned off, the system begins the passive arming process. If all zones are secure, normal arming occurs after expiration of an exit delay. If any zone becomes active during the exit delay, the process begins again.
Other features may also be incorporated in a vehicle security system. For example, U.S. Pat. No. 5,382,948 to Richmond discloses a vehicle security system including anti-carjacking features. The vehicle security system includes a speaker at the vehicle for the purpose of providing an acknowledgment signal, such as a chirp, to incidate that the supervisory control unit is armed/disarmed or to provide other audible response signals as well as intruder warning notices and siren functions. The system further includes a remote transmitter and receiver unit having a miniature speaker which provides an audible sound such as a chirp to indicate acknowledgement of a signal transmission, advise of the status of the supervisory control unit, etc. An LED is also provided for visual indication that a signal is being transmitted or that the battery strength is adequate. Unfortunately, for a typical vehicle security system, a number of important security system conditions may be of interest to the vehicle owner when away from the vehicle. A simple acknowledgement of a signal transmission or of an alarm indication may be of only limited value to the owner.